Spring barrel pumps

ABSTRACT

Spring barrel pump characterized by the fact that the bores ( 2 ) in which the pistons ( 4 ) move are provided by way of the spring barrel ( 1 ) diametrically to its axis (XX).

This invention has as its object a rotating spring barrel pump in whichthe pistons move into bores provided through the spring barrel,diametrically to its axis, by moving away under the effect of thecentrifugal force and by drawing closer by resting on an eccentric ring.

Such pumps are known by the patents WO 02/084105 of Oct. 24, 2002; US2004/065192 of Sep. 17, 2003; DE 198 42 120 of Sep. 21, 1998; DE 36 28769 of Aug. 25, 1986 and EP 0 812 985 of Jun. 3, 1997.

These known pumps all have the drawback of using complex means to ensurethe supplying and the conveying of the oil, which in practice preventstheir use for high turning speeds of the spring barrel and thereforelimits the usage thereof.

The pump according to the invention comprises both very simple andparticularly high-performing supplying and discharging means that allowits use at very high turning speeds of the spring barrel.

The pump according to the invention is a rotating spring barrel pump inwhich the pistons move into bores provided diametrically through saidspring barrel by moving away under the effect of the centrifugal forceand by drawing closer by resting on an eccentric ring, characterized bythe fact that said bores communicate: on the one hand with the supplyduct by means of ducts emptying into a chamber that is located behindthe rotating spring barrel, a chamber into which the supply ductempties; on the other hand, with the conveyor duct by means of acollector, applied against the rear surface of said spring barrel by aspring, whereby this collector is equipped with a cup that communicateswith said conveyor duct; whereby said collector is eccentric relative tothe axis of the spring barrel such that each of the ducts empties intosaid chamber during a half-turn and into the cup during a half-turn.

By way of nonlimiting example and to facilitate the comprehension of theinvention, the following was shown in the accompanying drawings:

FIG. 1: A longitudinal cutaway view of an embodiment of the invention.

FIG. 2: A view on an enlarged scale of a portion of FIG. 1, whereby theparts are in median position.

FIG. 3: A view corresponding to FIG. 2, after a rotation of 90°.

FIG. 4: A cutaway view along BB of FIG. 1.

By referring to these figures, it is seen that the pump that isindicated by the general reference P is driven by a motor M.

The pump P consists of a spring barrel 1 that, in the example shown, isa full cylindrical body, whose end 1 a is traversed, along a diameter,by a bore 2.

This bore 2 is separated into two equal portions 2 a, 2 b by a plug 3that is placed on the axis XX of the spring barrel 1.

In the bores 2 a, 2 b, two cylindrical flyweights 4 a and 4 b, whichproject slightly beyond the rear cylindrical portion 1 a of the springbarrel 1, slide freely.

The ends of the flyweights 4 a, 4 b that project beyond the springbarrel 1 a rest against a circular ring 5.

As is seen in FIG. 3, this ring is eccentric relative to the axis XX.

This pump is designed to be driven at very high speeds, on the order of25,000 rpm.

At such speeds, the flyweights 4 a, 4 b are moved away from the axis XXby the centrifugal force and are brought toward the center by the ring5, which is eccentric: this back-and-forth movement of the flyweights 4a, 4 b produces a pumping effect, whereby said flyweights act aspistons.

It is necessary that the hydraulic fluid can return into the bores 2during the spacing movement of the flyweights/pistons 4 and can beevacuated under pressure when these flyweights/pistons 4 are pushed backby the ring 5.

For this purpose, the bores 2 a and 2 b are each connected by a pipe 6a, 6 b to a chamber 7 into which the hydraulic fluid enters via anintake pipe 8.

A conveyor collector 9 is applied by a spring 10 against the flat rearsurface 11 of the rear portion 1 a of the spring barrel 1.

The end of said conveyor collector 9 that rests against the surface 11comprises a cylindrical cup 12 that communicates with a discharge duct13.

As is indicated in FIG. 2 by the broken line Z, the axis of the cup 12is eccentric relative to the axis XX of the spring barrel 1.

As is seen by comparing FIGS. 2 and 3, the result is that when thespring barrel 1 executes a rotation, in a first step, a half-turn,during which the piston 4 a moves away under the effect of thecentrifugal force, the duct 6 a communicates with the chamber 7, and thehydraulic fluid is drawn into the bore 2 a; then, in a second step,second half-turn, when the piston 4 a is pushed by the ring 5, which iseccentric, the fluid is conveyed from the bore 2 a by the duct 6 a thatthen is found in correspondence with the cup 12 because the latter iseccentric.

Thus, at each turn, the hydraulic fluid is drawn in and then fed back.

Furthermore, it is easy to act on the eccentricity of the ring 5 andthus to obtain a variable-capacity pump.

Preferably, the ring 5 consists of a roller bearing, whereby the ends ofthe pistons 4 rest against the inside ring of said roller bearing.

This inside ring is driven in rotation by the support exerted by thepistons, with a slight sliding of the latter.

A pump, such as the one shown in FIGS. 1 to 3, can be driven up to20,000 rpm and more without it being necessary to pressurize the supplyof the pump, and it can provide pressure up to 700 bar.

All of the forces are radial forces, which makes it possible to usecommon, less expensive means to ensure the sealing.

The collector 9 is preferably constituted to be hydrostaticallybalanced, whereby the surface area of its rear face is slightly largerthan that of the cup 12 and whereby the only object of the spring 10 isto ensure correct operation without pressure or at very low conveyorpressure.

In the example shown, a single bore 2 passes through the spring barrel1, but it is possible to use several bores that are each equipped withtwo pistons.

This invention makes it possible to produce a pump that has remarkablequalities with simple and inexpensive mechanical means.

1. Spring barrel pump of the type in which the pistons (4) move intobores (2 a, 2 b) provided through said spring barrel (10), diametricallyto its axis (XX), by moving away under the effect of the centrifugalforce and by drawing closer by resting on an eccentric ring (5),characterized by the fact that said bores (2 a, 2 b) communicate: on theone hand, with the supply duct (8) by means of ducts (6 a, 6 b) emptyinginto a chamber (7) that is located behind the spring barrel (1) intowhich said duct (8) empties; on the other hand, with the conveyor duct(13) by means of a collector (9), applied against the rear surface (11)of the spring barrel (1) by a spring (10), whereby this collector (9) isequipped with a cup (12) that communicates with said conveyor duct (13);whereby said collector (9) is eccentric relative to the axis (XX) of thespring barrel (1), such that each of the ducts (6 a, 6b) empties intothe chamber (7) during a half-turn and into the cup (12) during ahalf-turn.
 2. Pump according to claim 1, wherein the collector (9) isbalanced hydrostatically so as to be kept—by pressure—resting againstthe rear surface (11) of the spring barrel (1).
 3. Pump according toclaim 1, wherein the pump is a variable-capacity pump.